Chunk #36 — Converging Pathways Implicated in Neurogenesis and AD Pathology — Wnt, reelin and the low-density lipoprotein receptor family in neurogenesis and AD
A more recent study showed that in transgenic mice carrying human ε4 (apoE4) apoptosis of neural progenitor cells takes place after exposure of these mice to environmental enrichment (Levi and Michaelson, 2007) suggesting that at least part of the mechanism by which apoE4 induces susceptibility to AD is by compromising neurogenesis. In addition to apoE there are a variety of LDLR ligands which have been implicated in neurogenesis. Reelin is perhaps the best characterized of these neurogenic factors. Reelin is highly regulated during embryogenesis and functions to guide neuroblasts towards their destinations during lamination of the cortex [For review see (Herz and Chen, 2006)]. During adulthood reelin continues to be expressed from interneurons of the brain and particularly from pyramidal neurons of the entorhinal cortex, which send major projections to the DG, as well as receive projections from CA1 and CA3 regions of the hippocampus (Pesold et al., 1998; Ramos-Moreno et al., 2006). Reelin expression has been shown to mediate the migration of neuroblasts and direct cell fate determination of adult NSC (Heinrich et al., 2006; Won et al., 2006;
